//method and field
#include <stdio.h>

int age = 18;
char name[] = "jack";
int d = 3;
int f = 5;

void m1() {
    printf("d: %d, f: %d\n", d, f);
}

//extern int x;
//extern int y;
//int addtwonum() {
//    return x + y;
//}